从菠菜中提取叶绿素实验方法的改进

以菠菜为研究对象,在石英砂和碳酸钙的加入下,充分研磨后工业乙醇室温浸泡,可以提取到的叶绿素含量为0.682mg/g.操作简单,设备要求较低,原料价廉易得,叶绿素提取率高,进行层析时现象更为明显.     

H2BPMPBD和HAP协同萃取Ln(Ⅲ)

镧系元素;H2BPMPBD和HAP协同萃取Ln(Ⅲ)     

中性萃取剂协同萃取研究

前言自从发现协同萃取以来,许多作者对协同萃取进行了广泛的研究。Reddy等人应用亚砜等中性萃取剂研究了两种中性萃取剂的协同萃取(以下简称B-B类协萃),认为在第一萃取剂(S~Ⅰ)浓度([S~Ⅰ])固定时,萃取分配比D的对数值对第二萃取剂(S~Ⅱ)的浓度([S~Ⅱ])的对数值作图是直线,其斜率为S~Ⅱ的溶剂化数n,随[S~Ⅰ]的增加直线斜率逐渐下降。似乎难以用斜率分析法来确定溶剂化数目。本文研究了二-正-辛基亚砜(以下简称DOSO),TBP和TOPO从NH_4SCN溶液中萃取Ce(Ⅲ)。分析了实验数据,提出了B-B类协萃分配比D的计算公式。     

H2BPMPED和Dipy协同萃取Ln(Ⅲ)的研究

4-酰代双吡唑酮是一类以吡唑酮为端基的脂肪族或芳香族非环四齿β-二酮,具有很强的配位能力.近年来,人们相继合成了一些具有明显应用前景的这类螯合剂,并对其在溶剂萃取、荧光分析等方面作了大量工作[1-4].我们合成了双(1＇-苯基-3＇-甲基-5＇-氧代吡唑-4＇-基)乙二酮(H2BPMPED).研究了它和2,2'-联吡啶(Dipy)的氯仿溶液从硝酸介质中对部分镧系离子的协同萃取.用斜率法确定了协萃合物的组成为LnBPMPED@HBPMPED@Dipy,测定了它们的半萃取pH值和热力学函数.     

伯胺N1923氯仿萃取盐酸和磷酸振荡反应的量热法研究

萃取振荡反应;微量量热法;伯胺N1923氯仿萃取盐酸和磷酸振荡反应的量热法研究     

双水相萃取体系的研究

有机溶剂;分相机理;双水相萃取体系的研究     

浊点萃取-火焰原子吸收光谱法测定菠菜中镁、锌和铜

在pH 8.0缓冲溶液中,以8-羟基喹啉为螯合剂,镁、锌和铜均与8-羟基喹啉生成螯合物,加入Triton X-100表面活性剂用浊点萃取分离富集菠菜样品中镁、锌和铜。分取部分表面活性剂相用乙醇定容至25mL,所得溶液直接用火焰原子吸收光谱法进行测定。对影响浊点萃取的因素和共存离子的干扰等进行了试验并予以优化。镁、锌和铜的检出限(3s/k)依次为0.057,0.064,0.032mg.L-1。应用此法测定了大叶菠菜和小叶菠菜中3种元素的含量,在两种样品中用标准加入法进行方法的回收试验,测得镁的回收率在93.3%～100.5%之间;锌的回收率在91.7%～97.9%之间;铜的回收率在94.0%～107.1%之间。     

多元协同萃取的研究 Ⅲ.AAB类三元体系对Nd(Ⅲ)的协同萃取

本文对1-苯基-3-甲基-4-乙酰基吡唑啉酮-5(PMHP文中用HA表示)和2-噻吩甲酰三氟丙酮(TTA用HT表示)与甲基膦酸二异戊酯(DiAMP用B表示)和二戊基亚砜(DASO用S表示)这几种萃取剂的甲苯溶液构成的两组AAB类三元体系,从高氯酸底液中萃取轻稀土元素Nd(Ⅲ)的协萃机理进行了研究。用斜率法测定了Nd~(3+)(≤10~(-4)mol·1~(-1)/NaClO_4(μ=0.1)/PMHP-TTA-DiAMP-C_6H_5CH_3体系的三元协萃物组成分别为NdAT_2·B和NdAT_2·B_2,体系平衡常数分别为K_(ATB)_1=7.0×10~(-2),K_(ATB)_2=20.9(25℃)。同时测定了Nd~(3+)(≤10~(-4)mol·1~(-1)/NaClO_4,HClO_4(μ=0.1)/PMHP-TTA-DASO-C_6H_5CH_3体系协萃物分别为NdA_2T·S和NdA_2T·S_2,测定的平衡常数平均值分别为K_(ATS)_1=5.2×10~(-2),K_(ATS)_2=2.8(25℃,平均值)。     

萃取剂HPMBP与N7301协同萃取Pd（Ⅱ）的平衡研究

有关HPMBP与胺类萃取剂的缔合问题,曾有报道,而且有光谱证实,其中 HPMBP 与TOA、TOMA 之间的缔合常数,也曾被测定。当胺的浓度超过某一值时,HPMBP 与伯胺N_(1923)、叔胺 N_(7301)均对 Pd(Ⅱ)出现反协萃现     

双（正辛基亚磺酰）乙烷—磷酸三丁酯体系协同萃取钯的性能和机理研究

合成了烷基双亚砜类化合物（正辛基亚磺酰）乙烷Ｃ８Ｈ１７－Ｏ＝２－（ＳＨ２）２－Ｏ＝Ｓ－Ｃ８Ｈ１７（简称ＢＯＳＥ），研究了ＢＯＳＥ－磷酸三丁酯（ＴＢＰ）二元中性体系不Ｐｄ（Ⅱ）的协同萃取行为。试验表明，在４－７ｍｏｌ／Ｌ ＨＣｌ介质中，该体系能定量地协同萃取Ｐｄ（Ⅱ）。还研究了协萃Ｐｄ（Ⅱ）的各种条件；Ｐｄ（Ⅱ）萃合物的反萃方法，萃取容量；共存离子的干扰情况，用本协萃体系对合成样品中的Ｐｄ（Ⅱ）进行     

油莱中叶绿素的提取及稳定性

研究了浸提法提取油菜叶绿素的最佳工艺条件及稳定性。结果表明,浸提法的最佳提取工艺条件为：以无水乙醇为提取剂,料液比为1：10（g／mL）,在70℃下提取4h。叶绿素在近中性或偏碱性介质环境中性质基本稳定,随着氧化剂浓度的增加其分解程度不断加大,且其光稳定性降低。     

杂粮中总黄酮的提取及含量测定的实验设计

通过学生分组，采用溶剂提取法，超声提取法和微波提取法等提取方法，测定了小米、糜子、青稞、荞麦和高梁等杂粮中黄酮含量，结果表明5种杂粮中，青稞中总黄酮的含量最高。该综合实验能够锻炼大学生运用所学实验技术解决实际问题的能力，适合作为高年级本科综合实验项目开设。     

土壤中的砷在菠菜中的富集规律研究

通过盆栽试验研究了不同污染条件下菠菜对As的吸收富集规律。结果表明,菠菜叶片中As含量与土壤污染指数之间呈指数相关,相关性达到了极显著水平；而菠菜根中As含量与土壤As含量之间为线性相关。从结果中还可见,在盆栽条件下,土壤中As含量达到60mg·kg~(-1)时,菠菜中As含量才有可能超过食品卫生限量标准。这个土壤含量值比现行的国家标准高了2倍。由于蔬菜中的As限量卫生标准是根据每人每日允许摄入量(ADI)来确定的,而土壤中的限量标准则是根据土壤背景值调查资料统计得到的,因此在评价土壤环境以及蔬菜的安全质量时,会出现污染的土壤上生产出合格蔬菜的尴尬情况,说明两者之间的联系还需进一步研究。     

检验菠菜中的铁元素

人教版普通高中教科书《化学第一册(必修)》(2019年第1版)中第71页新增研究与实践活动——检验食品中的铁元素,教材给出了可供参考的实验方案,在菠菜汁中加入稀硝酸和硫氰化钾溶液进行检验,由于硝酸和硫氰化钾作用也可能产生红色,通过进行空白实验证明该方法存在干扰.设计了2种代表性实验方案:焯水检验法和灼烧检验法,通过实验...     

Optimization of Chlorophyllase-catalyzed Hydrolysis of Chlorophyll in Monophasic Organic Solvent Media

The effects of selected reaction parameters, including solvent hydrophobicity, initial water activity, agitation speed, temperature and enzyme concentration, on the biocatalytic efficiency of a chlorophyllase enzymatic extract from Phaeodactylum tricornutum in neat organic solvent media were investigated. The highest chlorophyllase specific activity of 322 nmol hydrolyzed chlorophyll per gram of protein per minute and bioconversion yield of 91% were obtained in the reaction mixture of hexane/2-octanone (98.3:1.7, v/v), at a controlled initial water activity of 0.90. R _O/A value, which is the ratio of the specific activity in the organic solvent to that in the aqueous/miscible organic solvent medium, was 1.5 × 10⁻³. To reduce the substrate diffusional limitations, the appropriate agitation speed and enzyme concentration were determined. The optimum temperature for maximal enzymatic activity and activation energy were 35°C and 105.0 kJ/mol, respectively. Although the catalytic efficiency of chlorphyllase in the neat organic solvent mixture was lower than that in the aqueous medium, its half-life time in the first environment at temperature ranging from 35 to 50°C was increased by 5.0 to 15.0 times.     

A Green Method of Extracting and Recovering Flavonoids from Acanthopanax senticosus Using Deep Eutectic Solvents

In recent years, green extraction of bioactive compounds from herbal medicines has generated widespread interest. Deep eutectic solvents (DES) have widely replaced traditional organic solvents in the extraction process. In this study, the efficiencies of eight DESs in extracting flavonoids from Acanthopanax senticosus (AS) were compared. Response surface methodology (RSM) was employed to optimize the independent variable including ultrasonic power, water content, solid-liquid ratio, extraction temperature, and extraction time. DES composed of glycerol and levulinic acid (1:1) was chosen as the most suitable extraction medium. Optimal conditions were ultrasonic power of 500 W, water content of 28%, solid-liquid ratio of 1:18 g·mL⁻¹, extraction temperature of 55 °C, and extraction time of 73 min. The extraction yield of total flavonoids reached 23.928 ± 0.071 mg·g⁻¹, which was 40.7% higher compared with ultrasonic-assisted ethanol extraction. Macroporous resin (D-101, HPD-600, S-8 and AB-8) was used to recover flavonoids from extracts. The AB-8 resin showed higher adsorption/desorption performance, with a recovery rate of total flavonoids of up to 71.56 ± 0.256%. In addition, DES solvent could efficiently be reused twice. In summary, ultrasonic-assisted DES combined with the macroporous resin enrichment method is exceptionally effective in recovering flavonoids from AS, and provides a promising environmentally friendly and recyclable strategy for flavonoid extraction from natural plant sources.     

Extracting and trapping biogenic volatile organic compounds stored in plant species

Biogenic volatile organic compounds (BVOCs), released by practically all plants, have important atmospheric and ecological consequences. Because BVOC-emission measurements are especially tedious, complex and extremely variable between species, two approaches have been used in scientific studies to try to estimate BVOC-emission types and rates from plant species. The first, which has known little success, involves grouping species according to plant-taxonomy criteria (typically, genus and family). The second involves studying the correlation between BVOC content and emission (i.e. how leaf content could be used to estimate emissions). The latter strategy has provided controversial results, partly because BVOCs are amazingly chemically diverse, and, as a result, techniques used to study plant BVOC content, which we review, cannot be equally adequate for all analytes.In order to choose an adequate technique, two patterns must be distinguished. Specifically stored compounds - mainly monoterpenes and sesquiterpenes that dominate the essential oil obtained from a plant - are permanently and massively present in specific storage structures (e.g., secretory cavities, trichomes) of the order of μg/g-mg/g and usually allow emissions to occur during stress periods when terpenes are weakly synthesized. These BVOCs can be studied directly through traditional extraction techniques (e.g., hydrodistillation) and novel techniques (e.g., application of microwaves and ultrasound), and indirectly by trapping techniques involving the collection, within adsorbent material, of BVOCs present in the headspace of a plant.Non-specifically stored compounds (e.g., isoprene, 2-methyl-3-buten-2-ol, and, in species without storage structures, monoterpenes and sesquiterpenes) can only be temporarily accumulated in leaf aqueous and lipid phases in small concentrations of the order of ng/g. As a result, studying their concentration in leaves requires the use of trapping techniques, more sensitive to trace amounts. Unlike for specifically stored BVOCs, knowledge of the concentration of non-specifically stored BVOCs cannot provide any information regarding the emission potential of a species but, instead, provides crucial information to understand why BVOC emissions may be uncoupled from the physiological processes that drive their synthesis.We describe both extracting and trapping techniques and discuss them in terms of the technical choices that may cause losses of thermolabile constituents, chemical transformations, different volatile recoveries and suitability to represent plant content of BVOCs faithfully. The second part of this review addresses technical shortcomings and biological and environmental factors that may alter the correlations between BVOC content and emission from plants.     

微型固相萃取柱结合胃袋式大体积进样-气相色谱-质谱法同时快速测定菠菜中的13种有机磷农药残留

利用微型固相萃取柱对样品进行前处理,采用胃袋式大体积进样技术结合气相色谱-质谱(GC-MS),建立了菠菜中13种有机磷农药残留的同时快速分析方法。以保留时间和特征离子丰度比定性,以峰面积外标法定量,以3倍信噪比实验值确定方法的检出限(LODs),以10倍信噪比实验值确定方法的定量限(LOQs)。结果表明,除乐果外,其余12种有机磷农药的添加回收率为76.8%～114.0%,相对标准偏差为1.5%～17.6%,LODs为0.5～25 μg/kg。该方法前处理简单快速,分析成本低,分析时间短,灵敏度、准确度和精密度均符合农药多残留检测技术的要求,适用于食品中多种有机磷农药残留的快速灵敏检测。     

Kinetic Study on Chlorophyll and Antioxidant Activity from Polyscias fruticosa (L.) Harms Leaves via Microwave-Assisted Extraction

Polyscias fruticosa (L.) leaves contain significant bioactive compounds with high antioxidant activity such as chlorophylls, total polyphenols, etc. but these have still been underutilized. In this study, the kinetics of chlorophyll and antioxidant activity extraction from P. fruticosa leaves by microwave-assisted extraction (MAE) were investigated. Microwave power was 300, 450, or 600 (W); the ratio of material/solvent varied from 1:40 to 1:80 (g/mL). In this study, the second-order kinetic model successfully predicted the change of chlorophyll and antioxidant activity during MAE. The increase of microwave power or/and the solvent amount increased saturated extraction efficiency and the extraction rate constant. However, the saturated concentration of chlorophyll and antioxidant activity increased with the increment of microwave power and the decrease in solvent amount.     

溶剂极性控制下的煤抽余物吸附甲烷能力研究

基于原煤和有机溶剂抽余物的等温吸附实验结果,对比分析溶剂极性与其煤抽余物吸附甲烷能力变化关系,探讨抽提溶剂极性差异对煤抽余物吸附甲烷能力控制的地球化学机理。结果表明,煤溶剂抽余物等温吸附甲烷曲线都遵循Langmuir方程,且二硫化碳(CS₂)和苯(C₆H₆)溶剂抽提作用增大了煤吸附甲烷量,四氢呋喃(THF)和丙酮溶剂抽提作用减小了煤吸附甲烷量。实验发现,煤抽余物吸附甲烷能力变化与抽提溶剂极性成负相关关系,该现象可用相似相容原理解释:CS₂和C₆H₆溶剂极性较弱,抽提出较多具有非极性结构(-CH₃和-CH₂-)的烷烃和芳烃,为甲烷在煤表面吸附增多了吸附位而增强了抽余物吸附甲烷能力,THF和丙酮溶剂极性较强,抽提出较多具有极性结构(-CHO、-OH、和-COOH)的非烃和沥青质,减少了吸附位而降低煤抽余物的甲烷吸附能力。